\section{Related Work}
Several e-Science based works, centered on giving users access to Semantic domain data, were available as of this writing.  An example of such work, with obvious usage of Semantic Web technology, is the VSTO observatory [1][2].  The underlying theme of the VSTO observatory is to present a system for integrating data from heterogeneous subdomains in astronomy.  In particular, the subdomains of solar physics, space physics, and solar-terrestrial physics were of interest.  To facilitate this heterogeneous data integration, a series of OWL-based ontologies are defined to allow for importing of concepts across domains.  This use of OWL-based ontologies facilitated a data framework capable of providing access to distributed and heterogeneous data sets --- as though derived from a single source.  From a user perspective, the VSTO observatory caters to a broad range of user backgrounds, with varying degrees of training in different domains.  

An alternate but similar project to VSTO is the Stellaris system [8].  As outlined by its creators, Stellaris has four key objectives.  The first of these objectives is to provide a user interface compatible with multiple data standards (and domains) as well as several existing data registry systems.  Likewise, the other three objectives largely deal with providing support for flexible domain data as well as cross-domain data integration.

While several other projects deal with heterogeneous data integration [5][6][9], others have themes centered on education of non-experts in one or more system target domains [11].  Likewise, many other works primarily focused on issues underlying data mining and data retrieval [7][10], which could both be seen as subproblems within eScience architectures. 

While StarGazer is not presently focused on domain data integration, it is designed with Semantic Web driven usability in mind.  In addition, while many of these eScience applications could be useful  in field research settings (in particular, the VSTO observatory), none seem directly fitted (e.g., providing mobile computing based versions) for this purpose.

In addition to the aforementioned e-Science oriented work, much research has been done on defining domain ontologies for Astronomy and its sub-disciplines.  Despite a unifying domain theme, the objectives of these ontologies (that is, what kinds of functionality they aim to facilitate) are quite various.  One example deals with goal-based data querying, such that information retrieval queries are made more domain intuitive, versus standard database lookup [3][12].  Likewise, alternate work deals with integration of domain data from heterogeneous sources [4].

In the StarGazer domain ontology, one of the primary objectives is to facilitate class hierarchy based inference (see Section \ref{functionality}).  It was not of particular concern to us to use this ontology to facilitate more domain-intuitive querying.  The main reason for this is that StarGazer's front-end (see Figure \ref{fig2}) currently doesn't allow users to directly write queries to its knowledge base.  However, this is something we may want to consider as we expand the functionality of StarGazer's front-end.